One last command that might be useful allows you to flush all the IP
accounting rules you have configured. This is most useful when you want to
radically alter your ruleset without rebooting the machine.

The -f argument in combination with the
ipfwadm command will flush all of the rules of the type
you specify. ipchains supports the -F
argument, which does the same:

# ipfwadm -A -f

or:

# ipchains -F

or:

# iptables -F

This flushes all of your configured IP accounting rules, removing them all
and saving you having to remove each of them individually. Note that flushing
the rules with ipchains does not cause any user-defined
chains to be removed, only the rules within them.